Field-angle-resolved specific heat and thermal conductivity in the vortex phase of UPd2Al3

The field-angle-dependent specific heat and thermal conductivity in the vortex phase of $\mathrm{U}{\mathrm{Pd}}_{2}{\mathrm{Al}}_{3}$ is studied using the Doppler shift approximation for the low-energy quasiparticle excitations, mostly in the superclean limit with negligible scattering rate $\ensuremath{\Gamma}$. We first give a concise presentation of the calculation procedure of magnetothermal properties with vortex and FS averages performed numerically. The comparison of calculated field-angle oscillations and the experimental results obtained previously leads to a strong reduction of the possible SC candidate states in $\mathrm{U}{\mathrm{Pd}}_{2}{\mathrm{Al}}_{3}$. The possible SC gap functions have node lines in hexagonal symmetry planes containing either the zone center or the AF zone boundary along $c$. Node lines in nonsymmetry planes can be excluded. We also calculate the field and temperature dependence of field-angular oscillation amplitudes. We suggest that the observed nonmonotonic field dependence and sign reversal of the oscillation amplitude may be due to small deviations from unitary scattering. We briefly discuss the influence of a finite $\ensuremath{\Gamma}$ on the field and angle dependence of thermal conductivity.